Endless sound record and mechanism therefor



Jan. 16, 1923.

L. DE FOREST.

ENDLESS souwo RECORD AND MECHANISM THEREFOR.

2 SHEETSSHEE1 1.

FILED OCT. 5,1920

Sn h wmlal wfoia BY ATTORNEY Jan. 16, 1923. 1,442,682. L. DE FOREST.

ENDLESS SOUND RECORD AND MECHANISM THEREFOR.

FILED OCT. 5, 1920. 2 SHEETSSHEY 2.

INVENTOR Sn 0h BY ATTORNEYgg Patented Jan. 16, 1923.

UNITED STATES LEEm: romas'r, 01 NEW YORK, N. ,Y.

ENDLESS SOUND RECORD AND MECHANISM THEBEFOE Application filed Octopu- 5, 1920. Serial No. 414,882.

To all 'llllO'llL if may concern:

Be it known that v I, LEE on FORES'I, a citizen of the United States, and a resident of New York, in the county and State of New York, have made a certain new and useful Invention in Endless Sound Record and Mechanism Therefor, of which the following is a specification.

This invention relates to an endless sound record and mechanism for use in connection therewith, such as may be employed in connection with phonographs, or thelike.

The object of the invention is to provide an endless sound record in which a record of exceedingly great length may be made on material of exceptional and relatively small area.

A further object of the invention is to provide means for preserving the record made in accordance with my invention during its use.

A further object of the invention is to provide a sound record and mechanism for.

use in reproducing the same which is simple in structure, eflicient in operation, and economical in manufacture.

Further objects of the invention will appear more fully hereinafter.

The invention consists substantially in the construction, location and relative arrangement of parts, all as will be more fully hereinafter set forth. v

Referring to the drawings:-

Fig. 1 illustrates a portion. of an endless film record embodying my invention-.-

F ig. 2 is a similarview of a portion o f the same.

Fig. 3 is a diagrammatic view partially in section of the reproducer mechanism employed in accordance with my invention.

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 3 and looking in the direction of the arrows. i I

Fig. 5 is a plan view largely diagrammatic showing reproducing mechanism and arrangement embodying my invention.

F ig. 6 is a sectional view, similarly largely diagrammatic, taken on the line 6.-6 of j The same part is designated by the same reference character Wherever it occurs throughout the several views.

In my co-pending applications, Serial No. 324,684, filed September 18, 1919, and Serial No. 332,342, filed October 21, 1919, I have shown and described an endless film strip and means for enabling the free movement thereof in the usual well known manner of -the reproducer wherein the film or other type of sound record is, for the purpose of illustrating the invention therein involved,

1 plitudesof wave forms, or photographic intensities representing sound waves. The first of the above-identified applications is primarily directed to means for winding and unwinding a coiled film and it is among the special purposes of my present application to incorporate herein subject-matter shown but not claimed in my said above-identified application. course, that where sound waves or light rays are photographically produced on the ribbon or strip that, in order toenable reproduction, the film was described in that instance' as being transparent. In accordance with my present invention I employ an opaque or non-transparent film, ribbon, or tape, such as paper, with the sound record photographically printed or otherwise made thereon. In the drawings 1 designates such a paper or other suitable opaque tape or ribbon with any desired number of parallel tracks of black or colored sound record on It will be understood, of

onesurfaoe thereof. This tape or the like travels longitudinally across a brightly illuminated region lighted by the member 2 tive cathode mirror 11, grid electrode anode.

9, etc. The light reflected from the tape 4 can only reach the cell 6 through the long and narrow slit 12 contained in the nozzle 5 of the envelope 10. The plane of the slit is vertical to the plane of the travelling tape 1 and the long axis of the slit is placed at right angles to the direction in which the tape is travelling. By means of this arrangement the image of the black line or sound record of varying transverse width or amplitude, varying, of course, in accordance with the original sound waves recorded thereon, is thrown up into the slot 12 of the nozzle 5. Thus the white light from the unblackened rtion of the tape or ribbon 1 directly be ow the slit at any given instance ons - I i is the only light which can fall upon the photo-electric cell. The intensity of this ight is inversely proportional to the height of the sound record, track or line on the tape 1 at the point thereof. which lies directly opposite the narrow slit 12. Thus the height or degree of the blackness or opacity of the dark track or both determines the amount of light falling at any instant on the photofilm,I am able to use bot-h sides thereof by twisting the ends of the tape one half a turn at any point between the ends thereof and then cementing the ends thereof together as clearly shown in Fig. 1. It will be apparent that by means of this arra ement I can use one track of recorded soun of twice the length possible if an untwisted film, such as shown in 111 two co-pending applications hereinabove identified, were shown. lh Fig. 1, 13 illustrates one surface of the tfipe and 14 the other surface thereof. The tape is twisted by a half turn between its ends before the ends are cemented as at 15 so that the surface 1 3 meets and forms a continuation of the surface 14, Then, as shown in Fig. 1, a continuous spiral linear track 16, marked on one side of the tape, will, on its second turn, appear on the reverse side of the tape, on the third turn on the-original side of the tape, etc, until its end is reached. Such an endless twisted tape can be rolled up in a c0il and unrolled in any suitable manner, for example, as shown in my two co-pending applicationsv first hereinbefore identified, and thus driven continuously.

, Thus, if a tape is formed, say, 800 ft. in

length, with eight widths of track or sound record on each face thereof, the entire track will be continuous from its beginning to its end, that is, will be 12800 ft. in length. I have obtained excellent'reproduction by such a system as I have herein described when the film or tape travels at a speed of 1 ft. per second. Thus it will be seen that by means of an arrangement as herein shown, I am able to obtain a phonograph record over 3% hrs. in length, in other words, in accordance with my invention, to obtain on a single record of 800 ft. in length, wound into atightly fitting spiral coil soastoconsumebut an exceeding] small amount of space, a continuous soun record of any opera, s eh, or the like, whiph to reproduce woul normally require 31} hrs. This could be modifiedat will, it will be readily understood, by varying the width of the tape or the length thereof, or the size of the sound record track as desired.=

Where the tape is wound upon itself in the form of a spiral or coil, as illustrated n my two co'pending applications first hereinbefore identified, and wherein the tape is crmtinuously movin and is rolled up and unrolled continuous y, as described, the inner portions are always slightly slipping over the outer ones, as all portions of the film gradually travel from the outside to the inside of the coil. This slipping action would in time scratch the surface of the film and impair sound record therein. Toprotect the film from such possible injury, I

prefer to use two thin ribbons of paper, silk, or other suitable sinoot maas the film, and rolled u in the coil with the film on each side of t e film throughout its length, so that in case of slippage, the slippage will occur between ribbon and ribbon and not in any instance between film and film. Thus, referring to Fig. 5, the film is illustrated by reference numeral 1, and the ribbon on each side thereof is illustrated by reference numerals 15 and 16.

some means must be provided to enable the reproduction of the sound records contained on the film itself. Where the sound record is contained on an opaque tape or film, this problem becomes a simple one in that the ribbon may be at asuitable point separated from the film, due to its natural, though limited, elasticity, and the light reflecting system diagrammaticall illustrated in Fig. 3 be thus employed. film is of the transparent type, a different problem is encountered and while many means may be devised for handling under thosecircumstances such type of film, in

Figs. 5 and 6 I have illustrated one means for enabling the reproduction of the sound record therein.- 20 designates the light chamber and 21 the photo-electric cell cham .ber. Suitable Spreaders 22 and 23 are sitioned between the film 1 and the ribbons 15 11 and 16 out of contact with the film, however, to permit the free passage of the film without marring the same, due to contact there with, while at the same time spreading the ribbons 15 and 16 in the manner shown in Fig. 5. The spreaders 22 and 23 consist of closed tubestor channels shown best in Fig. 6 communicating directly with the respective chambers 20 and 21 and preferably at a bone 15, 16 and the film, 1, as clearly shown. The passages 22 and 23 are provided therein with reflecting surfaces 26 so that the ,light emanating from the lamp or other source f light 2 contained in the chamber 20 130 lazed terial, these ribbons being of the same length 85 When this system is employed, it will be apparent that 9,5

here, however, the 105 plane below the lower edge of the ribis reflected by the mirrors 26 through the film and to the photo-electric cell 6 in a manner which Wlll be readily understood. Suitable guide rolls 30 positioned on opposite sides of the reproducing mechanism serve to return the ribbon in its protecting position about the film.

Many modifications and changes in details will readily occur to those skilled in the art without departing from the spirit and scope of my invention as defined in the claims. Therefore, what I claim as new and useful, of my own invention, and desire to secure by Letters Patent is 1. An endless film having a continuous spiral record thereon extending on both sides thereof.

2. The combination with a film havin a record thereon, of a. protective ribbon adjacent said film to move therewith, and means for separating said ribbon from said film at the reproduction exposure point in the travel of said film.

3. The combination with a film having a record thereon, of a protective ribbon adjacent said film to move therewith, and means for exposing said film without hindrance from said ribbon at the reproduction point in the travel of said film.

4. The combination with an endless film having a record thereon, of an endless protective ribbon positioned on each side of said film to move therewith, and means for exposing said film without hindrance from said ribbons at the reproduction point in the travel of said film.

In testimony whereof I have hereunto set my hand on this 29th day of September A. D. 1920,

LEE m: FOREST. 

